Question

Max has a bag of plain and cat’s eye marbles. There are 30 plain marbles and 7 cat’s eyes. He picks one marble and sets it aside. Then he picks another.

What is the probability that he picked 2 cat’s eye marbles?

Answer 1

0.19

Explanation:

To compute the probability that Max picked cat's eye marble in second chance, their are two ways that is:

1. He picked plain marble first time then he picked cat's eye marble in second time.
2. He picked cat's eye marble first time also.

Their are two type of marbles: Plain Marble (P) and Cat's eye Marble (C)

∴ Probability that Max picked cat's eye marble in second chance = P( P then C) + P(C then C)

⇒
`(30)/(37) *(7)/(36)+(7)/(37) *(6)/(36)`

= 0.19